Painting a steel tank

[halocline]

I would try the cover idea or some other way to live with the tank without damaging the existing paint. Anything you do yourself is likely to not last very long. The really durable finishes (like faber tanks have) is impossible to re-create on your own. And you should definitely check the rules in your country about hydro testing and re-painting. There are shops here that would not pass a tank that has been painted with some processes that involve heat.

I have used paint stripper on old beat up steel tanks that have colors over galvanized primer, and then re applied cold galvanizing compound, and it's worked well. But that's paint that is almost entirely zinc, and still the tanks are not as tough as modern hot-dipped galvanized tanks.

 

[JamesBon92007]

And how does it cope with the pressure form the tank straps on the wing/jacket? How long does the color last? and did you sand it with a sand paper?
Thanks

Since you already have a good paint job on the tank all you need to do is sand it until it is no longer shiny. The safest way to do this is probably by using #600 wet-or-dry sandpaper. I would use 1/4 of a sheet and sand it by hand, always sanding from top to bottom never sideways or in a circular motion. Once the shininess is gone what is normally used to remove any dust is called a "tack rag" or tack cloth." This will clean up the surface without introducing any contaminants that might cause compatibility problems (if you use the wrong finish over an existing finish it might not dry properly). For what you are doing I think a damp cloth (clean cotton wash cloth or whatever) should work fine so you can get by without the tack rag. Dry it with a clean towel and let it dry for a couple of hours to make sure it is completely dry. Mask the valve using masking tape and newspaper (or whatever is handy). Shake your can of paint for at least a couple of minutes. Spray from top to bottom, and bottom to top being careful to not apply too much paint or it will run (sag) and become a mess, but also make sure you apply enough paint to where it has an even gloss. Keep shaking the can of paint periodically during the painting process. Let dry thoroughly (probably overnight). With many spray paints you can apply a second coat (if needed) without sanding the first coat but personally I would sand it lightly between coats. The paint MUST be completely dry if you are going to sand it between coats.

It might be faster and easier to use #400 sandpaper (courser grit than #600) but tiny scratches might be visible under the paint. Steel wool can sometimes be used instead of sandpaper but I would never use it in a marine application because tiny fragments might get stuck in the old paint and cause rust spots later on.

If you wait several days before attaching the tank straps it should be fine but I would expect them to leave marks. You might wish to touch it up somewhere down the road so save the can of paint. Applying wet paint over dry will usually leave foggy-looking areas where the new and old paint overlap. This can be avoided by re-painting the entire tank once again but I would recommend doing the prep work all over again for the best results.

Personally I would not do this sanding job in a bath tub but I understand why it was suggested.

 

[oldschoolto]

Water used in wet sanding does two things.. 1: it removes the fine paint that is removed during the sanding so it is pushed back into the base coat and 2: it works as a lube to stop the sandpaper from getting to big of a bite.. you can , As body men do.. Use a rubber squeeze to remove the water film from the paint showing you how it's going.. The bathtub would be a easy place to do it.. But, you'll need to clean up the tub...

You're over thinking this... Give the tank a fast sanding (lightly) and spray it pink.. The paint will be so thin that it will not be any real difference then before...

Jim....